The present invention relates to a programming method of a non-volatile memory device.
In recent years, there has been an increasing demand for non-volatile memory devices which can be electrically programmed and erased and do not need a refresh function of rewriting data at specific intervals.
A non-volatile memory device generally includes a memory cell array in which cells for storing data are arranged in matrix form, and a page buffer for writing memory into specific cells of the memory cell array or reading memory stored in a specific cell. The page buffer includes a bit line pair connected to a specific memory cell, a register for temporarily storing data to be written into the memory cell array, or reading data of a specific cell from the memory cell array and temporarily storing the read data, a sense node for sensing the voltage level of a specific bit line or a specific register, and a bit line select unit for controlling whether the specific bit line is connected to the sense node.
In a typical program operation of the non-volatile memory device, a program operation is performed and a verify operation is then carried out. However, a problem arises because unnecessary steps are performed in a process of applying a program voltage to a selected word line and then applying a verify voltage to the selected word line, and a process of applying a program-prevention voltage (a first pass voltage) to unselected word lines and then applying a verify-prevention voltage (a second pass voltage) to the unselected word lines.
There is another problem in that overshooting is generated in the verify voltage due to the influence of the verify-prevention voltage applied to neighboring word lines when the verify voltage is applied.